Dna Sensor Based on MoS2/MWCNT/AgNPs Nanocomposites for Sensitive Electrochemical Detection of Hydroxyl Radicals

Oxidative stress is intricately linked to the production of reactive oxygen species, which act as the primary catalysts for cellular structural damage, encompassing proteins, lipids, and DNA. Specifically, the hydroxyl radical (·OH) is one of the most chemically reactive free radicals and is considered a major driver of oxidative DNA damage. This type of damage can play a role in the progression of several neurodegenerative diseases, including Parkinson's and Alzheimer's, along with malignant tumors. Hence, precise measurement of ·OH levels in human tissues, organs, and blood is essential for the diagnosis of these conditions. In this research, we introduce an electrochemical DNA sensor constructed from MoS₂/MWCNT/ silver nanoparticles (AgNPs) nanocomposites. The sensor employs 5′-sulfhydryl-modified single-stranded DNA (SH-DNA) anchored on AgNPs and enables sensitive detection of ·OH through oxidative damage to SH-DNA caused by ·OH generated through the Fenton reaction. The sensor's performance was thoroughly evaluated using a range of electrochemical techniques, including cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. The results demonstrate that the proposed sensor exhibits a low detection limit (46.88 μM) along with a wide linear range (50–5000 μM). Notably, it possesses high sensitivity and selectivity, showing great potential for early diagnosis and monitoring of oxidative stress-related diseases in the biomedical field.